The present invention relates to a safety cabinet for biohazard, that is, a clean worktable enabling a hazard to be prevented from being caused by a treatment of microorganism or causal organism for genetic manipulation in medical or pharmaceutical field or an investigation of the causal organism for an investigation of infection disease.
In the prior art, a safety cabinet is used as a primary barrier for physically isolating a human body or an environment from the microorganism or causal organism to be treated. In a prior art safety cabinet, an opening area of a front opening is fixed as disclosed by JP-A-62-132550, and a flow rate through the front opening is measured by a flow rate sensor so that a blower is controlled to keep the flow rate within a predetermined range even when HEPA filter as a cleaner is in clogging to cause a change in pressure loss thereof.
In the prior art safety cabinet, the opening area of the front opening is fixed at a predetermined value such as 200 mm to keep the flow rate through the front opening at a constant degree as disclosed by Japanese Industrial Standards K3800:2000. A worker extends his arm through the front opening into a working space to treat the microorganism or causal organism. Further, he looks into the working space through a front shutter above the front opening.